Circuit breaker



0, 1941- J. G. JACKSON ETAL 2,253,335

CIRCUIT BREAKER Original Filed March 25, 1955 IN VENTO 1'? J07??? 6'. .fackaan BY MZZaca 7. fllierz lessen the flame ejected from the vents.

Patented Dec. 30, 1941 V UNITED STATES PATENT OFFICE.

CIRCUIT BREAKER pany, Detroit, Mich.,

a. corporation of Michigan Original application March 25, 1935, Serial No. 12,798, now Patent No. 2,132,623, dated October 11, 1938. Divided and this application April vwmagaz nes Serial No. 205,064

4 Claims.

This invention relates to apparatus for making and breaking electrical circuits, and more particularly to an arc suppressor construction facilitating the rupture of arcs drawn between the cooperating contacts of such apparatus.

This application is a division of application Serial No. 12,798 filed March 25, 1935 for Circuit breakers now Patent Number 2,132,623, granted October 11, 1938.

One object of the invention is the provision of an improved form of arc suppressor for facilitating the rupture of arcs drawn between the cooperating contacts of an electric circuit breaker. Another object of the invention is to provide a magnetic arc suppressor U-shaped and formed of a plurality of stacked laminations.

A further object of the invention is the provi- 7 sion of a magnetic arc suppressor for an electric circuit breaker formed of a plurality of U-shaped laminations, directly stacked, without the provision of insulation other than incidental surface oxide and incidental air space.

Further objects and features of the invention will be readily apparent to those' skilled in the art from the following specification and the appended drawing illustrating certain preferred embodiments of the invention in which:

Figure 1 is a side elevational view of a circuit breaker in which the arc suppressor, according to the present invention, has been embodied, with a side of the enclosure cut away to show the interior of the breaker mechanism.

Figure 2 is a top plan view of the circuit breaker shown in Figure 1, with the cover and handle removed.

Figure 3 is a detailed sectional view on the line 3-3 of Figure 1.

4 is a view showing one of the laminations making up the arc suppressor.

Figure 5 is a perspectiy e yiew oi one ofathe insulating shields mounted about the cooperating contacts of the circuit breaker.

Referring to the drawing, in which like reference numerals indicate like parts, the enclosing structure for the circuit breaker comprises a base I and a cover 2. The ends of the cover adjacent to the top are provided with a plurality of slots 3 forming vents for the arc gases. The walls defining the slots are extended past the ends of the cover and are joined together by a bottom portion 4. The vent walls exercise a cooling action upon the arc gases and serve to The bottom portions 4 constitute baiiles for directing the arc gases away from the connectors. The

(ammo top of the cover is provided with a slot 5 through which extends an operating knob 6. The base I is in the form ofa shallow cup in which at opposite ends are disposed stationary contacts 1, 8. Contact I is secured to a conducting connector 9 leading to the exterior of the enclosure. Contact 8 is rigidly secured to one leg of a U-shaped bimetallic member II, to the other leg of which is rigidly secured a conducting connector I2 leading to the exterior of the breaker. The contact 8 and connector l2 have their ends bent over to engage the bottom of the legs of the bimetal II and are welded thereto to form a rigid permanent connection. The contact and connector are attached to the same face of the bimetal with the contact overlying the connector and insulated therefrom as by means of an insulating sheet l3. The contact 8 and connector l2 are rigidly secured to base I and thus support the bimetal II in operating position.

Over each of the contacts I and 8 is disposed an arc suppressor l4 formed of a plurality of thin, plate-like laminations of U-shape loosely supported upon the base I in spaced relation to the stationary contacts. The legs of the U are disposed on opposite sides of the path of movement of the movable contacts to be hereinafter described, and are held in position by means of the shields 15. The inside edges of the ends or legs of the U-shaped laminations have been provided, as shown, with small extensions forming pole faces tending to concentrate the magnetic flux at these portions. The shields l5 as shown in the drawing have been cut away to more clearly show the parts of the breaker. They embody a top portion l6 and an end portion l1 having a slot for receiving the movable contact. Side portions depend from the shield to engage the top lamination on the arc suppressor and other side portions l8 extend upwardly to seal the joint between the cover and the base. The top IE is open at the end of the enclosure to afiord passage for the arc gases between the side portions l8. Shields l9 are provided to seal off the end junctions between the cover and the base.

A bracket 2| is rigidly secured to the base I adjacent the top thereof and extends over the top [6 of one of the barriers l5. On this bracket is pivotally mounted a carrier 22. Upon the car- 50 rier 22 intermediate its ends are pivotally mounted a pair of plates 23 disposed on opposite sides of the carrier 22. A conducting bar 24 having contact faces 25 adjacent its ends is pivotally supported on the plates 23 by the pivot 26 which 55 also serves to join the plates 23 together for comrier 22.

1 operating springs 34 and 35 mon movement as a unit. The bar 24 is connect ed to the pivot 26 through the extension 21 and carrier 22 is similarly cut away to receive this extension in the off position of the breaker. The carrier 22 is provided with a pin adapted to be engaged by the surface on the plates 23 and serving as a stop therefor in the overload off position. The plates 23 are equipped with parallel notches 28 in which is disposed a flipper element having parallel legs 3| which are disposed in the notches 28 on opposite sides of the conducting bar'24 and carrier 22. The legs 3i of the flipper have a cross bar at their ends and beneath the bar 24 to which cross-bar the operating springs 34 and 35 are connected. A U-shaped operating member 36 is fulcrumed in grooves 31 in the bottom of the cup-shaped base I. The

. legs of U-shaped member 36 are disposed at the extreme sides of the enclosure and operate between stops 39 in the walls of base, I. The member 36 has parallel arms 4| integral therewith and at the extremities of these arms is supported a pin 42 to which the ends of operating springs 34 and 35 are secured, This'pin 42 may begrooved to retain the springs .at its ends in spaced relation to each other and to the moving parts. The carrier 22 is provided with an extension adapted to be engaged by the pin 42 to .liinit movement of. the member 36 and knob 6 in normal on position. The carrier 22 is further provided with a surface 48 engaged by pin 42 when the knob 5 is moved to the right from "overload off position to reset the breaker after it has been operated in response to an overload. To the member 36 is rigidly secured a shield 43 carrying the operating knob 8 which extends through the slot 5 the shield 43 serving to seal this slot. The carrier 22 is provided at its free end with a latching surface 44. This carrier is normally held in the position shown in Figure 1 by means of a latch 45. A supporting plate 46 is rigidly secured to the base I and is provided with grooves adjacent one end thereof. The latch 45 embodies a U-shaped element having legs 41 also provided with grooves adapted to enter and engage with those on the plate 46 to form a pivotal mounting'for the latch 45. The latching surface 44 on the carrier 22 is-engaged by the top ofthe slotbetween the legs 41 to latch the carrier .in place. The connecting portion of the U-shaped latch 45is return bent as shown to form a second U in a plane at right angles to the first. The legs of the second U are disposed on opposite sides of the. bimetal member II and to the leg 48 thereof disposed on the low expansion 5 sideof the bimetal an insulating abutment 49 is adjustmoun connection.

A bracket 5| is rigidly secured to the lfisel and a spring 52 connects the end of leg bracket 5| to bias the latch 45 toward the tedasbywns of a. stud and nut car- The operation of the breaker described above shouldbe readily apparent. With the parts in the on position as shown in Figure 1, movement' of the knob 6 toward the right will move the member 36 and the operating springs 34 and 35. Before these springs have reached the effective .dead center position the force of the springs on the flipper 29 will serve to move it within the slot 28 from the side shown in Figure 1 to the opposite side, thus quickly flipping the past dead center pobellcrank lever formed by nter-clockwise into the po- 7 sition and causing the plates 23 to rotate cou 43 t m affangemefiFBf parts is suchthat the. pin ,4

7 of the path of tra sition shown in Figure 3, moving the contact bar 24 to its oiT' position. The flipper slot is shown to be directed toward the left of the .bell crank pivot so that the operating springs 34' and 5 will exert a force tending'to rotate the bellcrank in a clock-wise direction, thus maintaining contact pressure even while the flipper is moving, as it can readily be seen that the torque on the bell crank will not change until the flipper actulo ally engages the side of the groove 28. This results in maintaining pressure on the contacts until it is sharply released by engagement of the flipper with the side of the groove 28. It is thus impossible to manipulate the knob 6 so as to have '15 a dead center position at which-there is no pressure on the contacts and it can be readily seen that the change in pressure on the contact from on" to off position will be brought about quickly regardless of the speed of operation of a the knob 6 since the operating-springs will always be quickly carried past their effective dead center position through the movement of the flipper; 'The'operation from the normal off position of Figure 3 to on position of Figure 1 is in reverse direction. With the parts in the normal off position of Figure 3, movement of the operating handle to the left will move the flipper 29 from the side of the groove shown to the opposite side to move the operating springs through 30 dead center position and thus move thecontacts 25 to engaged position. Upon overload, the bimetal H which is in series with the breaker circuit and is self-heated by the current therethrough, becomes heated'anhmoves in a clock- 5 wise direction to engage the stop 49 and move the latch 45 clockwise unti the latching surface 22 is released and moves upward under the bias of the operating springs 34 and 35.

The stop 38 is moved above'the pin 42 by this movement of the carrier 22 whereupon the member 36 and knob 6 move to their extreme position. In this movement of the carrier 22 to its released position, the plates 23 are prevented from rotat- 1 it is moved beyond 5 ing relative to the carrier by engagement of the surface 28 with the pin I0 and the contact bar 24 is thus quickly moved to oif" position with a snap action. Upon resetting, the knob 6 is moved to the right whereupon pin 42 engages the surface 50 on the carrier 22 and moves'the latching surface 44 downward into position to be engaged by the latch 45, if in the meantime the bimetal ll has cooled sufficiently to allow the latch to be pulled to its normal position by the spring 52. a When the surface 44Js@s engaged by latch the parts will be reset in the'nxnormal position as in Figure 3. Movement of the,

left will then move the breaker to its on position as inrFigure l.- It should be noted tha t the 2 will after e side hannot move the cradle to reset position until the flipper 3| has been moved to the opposit of the slot by the resetting movement of the dle.

The are suppressor of a plurality of U inations loosely di of the base i and The legs of the U l4 herein shown is built up sposed in recesses in the sides held therein by the shield I5. are disposed on opposite sides The laminations incidental insula to air space and them from each 0 5 upon the inside 44 whereupon the carrier.

mater 1 -shaped,- thin, plate-like lamvel of the conducting bar 24.

insulate them from any are which may be formed. The suppressor in its entirety consistssimply of the ordinary laminations built up without any positive attempt to secure insulation.

In connection with the arc suppressor herein described. it should be noted that the connectors 8 and I! have portions extending along side the arc suppressors and this results in a more complete turn about the laminations and hence increasesthe strength of the field induced by the current throughthe connecting member and, thus increases the emciency of the magnetic effect.

While certain preferred embodiments of the invention have been specifically described and illustrated, it is understood that the invention is notlimited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given its broadest possible interpretation within the terms of the following claims: V

What is claimed is:

1. In a circuit breaker, a stationary contact, a group of U-shaped magnetic laminations mounted over said contact, a contact movable between the legs of the U, a shield mounted over said laminations, saidshield'having a top portion serving as an insulating stop for the movable contact and an end portion slotted to receive and guide said contact and shielding the are from the interior of the breaker.

2. In a circuit breaker, a stationary contact having a substantially flat contaoting'surface, a movable contact arm carrying a substantially flat contact surface adjacent its end adapted to make butt contact with said stationary contact, a U- shaped magnetic arc suppressor disposed in spaced parallel relation to the surface of said stationary contact and with its legson, opposite sides of the path of movement of the movable contact, said suppressor comprising a directly stacked group of thin, plate-like magnetic lamination, and an insulating housing operating to form a local enclosure for said stationary and movable contacts and having one wall thereof provided with a slot for receiving and guiding said contact arm, and another wall serving as a limiting stop for the extreme separated position of the movable contact. v

3. In a circuit breaker, a stationary contact having a substantially fiat contacting surface, a movable contact arm carrying a substantially flat contact surface adjacent its end adapted to make butt contact with said stationary contact, a U- shaped magnetic arc suppressor disposed in spaced parallel relation to the surface of said stationary contact and with its legs on opposite sides of the path of movement of the movable contact, said suppressor comprising a directly stacked group of thin, plate-like magnetic laminations, an insulating housing-operating to form a local enclosure for said stationary movable contacts and having one wall thereof provided with a slot for receiving and guiding said contact arm, and another wall serving as a limiting stop for the extreme separated position of the movable contact, and a venting opening'in said housing for exit of the gaseous products of an are drawn 5 between the cooperating contacts.

cooperating contacts mounted over said laminations and providing holding means for maintaining them in position, said housing including a slotted portion receiving said contact arm to permit movement of said movable contact.

' JOHN G. JACKSON. wamlacnr. ALLEN. 

